Scour, respectively bleach, and rinse the feathers well clean, prepare
a bath, work the solution of five per cent., of the weight of feathers,
silver gray (Actein Gesellschaft fuer Anilin Fabrikation, Berlin),
feebly acidulated with sulphuric acid; enter the feathers in the cold,
work well to make the color dye up evenly; then raise the temperature
slowly under diligent working, to 170° F., continue at this temperature
for five to ten minutes, lift, rinse and dry.